So you think localizing @ARGV should also localize the (potentially open) ARGV filehandle too?

I personally believe that based on the principle of least surprise, I would indeed say so. Perl does magic worse than that already, and otherwise a localised @ARGV would be of little utility since one would want to use the above described technique (referring to your sub) as a cheap shortcut to

sub collect {
    join '', map {
        open my $fh, '<', $_ or warn "Can't open `$_': $!\n";
        <$fh>;
    } @_;
}
[download]

(But for the 2-args implicit openedness, of course.)

What exactly did you try? Localizing *ARGV worked for me exactly as I would have thought:

It doesn't work for me:

picard:~/tmp [11:26:38]$ perl -v | head -n 2

This is perl, v5.10.0 built for i486-linux-gnu-thread-multi
picard:~/tmp [11:26:42]$ cat ../domk.pl
#!/usr/bin/perl

use strict;
use warnings;

while (<>) {
    chomp;
    print "huzzah:".collect( $_ )."!\n";
}

sub collect {
    local *ARGV;
    @ARGV = @_;
    join '', <>;
}

__END__
picard:~/tmp [11:26:55]$ ls file? | ../domk.pl
Can't open file1: No such file or directory at ../domk.pl line 14.
huzzah:!
Can't open file2: No such file or directory at ../domk.pl line 14.
huzzah:!
Can't open : No such file or directory at ../domk.pl line 14.
huzzah:!
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But even if it did "work", as it did with you and kyle, it wouldn't be much dwimmy: in fact your output is not the same one would have got out of using the "expanded" sub above. The following example won't work on my box either, but you could try it:

#!/usr/bin/perl

use strict;
use warnings;
use Test::More 'no_plan';

sub dargv {
    local *ARGV;
    @ARGV = @_;
    <>;
}

sub dopen {
    map {
        open my $fh, '<', $_ or warn "Can't open `$_': $!\n";
        <$fh>;
    } @_;
}

while (<>) {
    chomp;
    is_deeply [dargv $_], [dopen $_] => $_;
}

__END__
[download]

Update: dopen has issues; this was discussed in another thread.